Table 1.

Seventeen USA cases associating exposure to a duodenoscope with infections or an outbreak of CRE or a related MDRO (listed in chronological order)

Case number	Approximate year infections, outbreak began	Reference number	Medical facility's state in USA	Type of resistant bacteria (eg, CRE)	Number of patients infected (or testing positive)	Number of patients who expired*	Sealed or unsealed duodenoscope model?	Were bacteria† recovered from a duodenoscope?	Was HLD being performed?	Was duodenoscope reportedly reprocessed according to manufacturer IFUs?	Case's possible cause(s)	Case's implemented measure(s), response
1	2012	7 22–24	PA	CRE (Klebsiella pneumoniae)	10-13	NR	Sealed	Yes	Yes	Yes	Ineffective duodenoscope reprocessing reported.	Began using EO gas to sterilize the duodenoscope, which reportedly terminated the outbreak. Periodic endoscope culturing performed.
2	2012	7 12 22	WA	CRE (AmpC-producing E. coli)	32	11	Sealed and unsealed	Yes	Yes	Yes	Several duodenoscopes reported to have at least one "critical defect" or "critical abnormality" requiring repair. Difficulty cleaning the elevator channel reported.	Began culturing, quarantining duodenoscopes.
3	2012	7 22	NY	CRE (K. pneumoniae)	15	NA	Sealed and unsealed	Yes	Yes	NR	NR	Began using EO gas to sterilize the duodenoscope.
4	2013 (2008‡)	29	FL§	CRE (K. pneumoniae)	7	At least 1	NR	Yes	NR	No	Inadequate cleaning of the duodenoscope's terminal part containing the elevator mechanism reported.	Received instruction on the correct cleaning and handling of duodenoscopes. Began performing additional manual cleaning of the duodenoscope's distal end using a brush.
5	2013	7–10 17 22	IL	CRE (NDM-1-producing E. coli)	35	2	Sealed	Yes	Yes	Yes	Difficulty cleaning the duodenoscope due to its complex design reported.	Began using EO gas to sterilize the duodenoscope, which reportedly terminated the outbreak.
6	2013	7 16	WI	CRE (NDM-1-producing E. coli)	3	NR	Sealed	No	Yes	Yes	Not determined.	Began using EO gas to sterilize the duodenoscope, which reportedly terminated the outbreak.
7	2013	22 27	CA	MDRO (Pseudomonas aeruginosa)	16	As many as 11	Sealed and unsealed	Yes	Yes	No	Ineffective duodenoscope reprocessing hypothesised possibly due to several factors including the device's design reported. Some duodenoscope reprocessing and storage lapses reported. Inadequate maintenance of automated endoscope reprocessors reported.	Implicated duodenoscopes removed from use. Began reprocessing all duodenoscopes twice.
8	2014	7	IL	CRE	3	NR	Sealed	Yes	NR	NR	Not determined.	NR
9	2014	7 20 22	CA	CRE (OXA-232-producing K. pneumoniae)	16	6	Sealed	No	Yes	Yes	Ineffective duodenoscope reprocessing reported.	Began supplementing manual cleaning and HLD with EO gas sterilization of duodenoscopes performed off-site. Implicated duodenoscopes removed from use.
10	2015	7 22 50	NC	CRE	18	1	Sealed	No	NR	NR	Not determined.	Began using EO gas to sterilize the duodenoscope.
11	2015 (2008¶)	28	USA§	CRE (K. pneumoniae)	7	NR	Unsealed	Yes	NR	No	Improper drying and storage of the duodenoscope reported.	Began routine culturing and testing of new duodenoscopes prior to and after each use. Implicated duodenoscopes removed from use.
12	2015	7	PA	CRE (K. pneumoniae)	3	NR	Sealed	Yes	NR	NR	Not determined.	NR
13	2015	51	CO	MDRO (ESBL-producing E. coli**)	9	3	Sealed	No	NR	NR	Not determined.	NR
14	2015	7	MA	MDRO (ceftriaxone-resistant E. coli)	3	NR	Sealed	NR	NR	NR	Not determined.	NR
15	2017	26	MA††	MDRO (mcr-1-positive K. pneumoniae)	2	NR	Sealed	Yes	Yes	Yes	Ineffective duodenoscope reprocessing reported. Persistant contamination of duodenoscopes "most likely due to a distal cap defect" reported.	Implicated duodenoscope removed from use and returned to the manufacturer for evaluation.
16	2017	33	USA††	MDRO (mcr-1-positive bacteria)	2	NR	Sealed	Not conclusive	NR	NR	Not determined.	An implicated duodenoscope was sequestered.
17	2018	52	USA	CRE (and other bacteria)	30	2	Unsealed	NR	Yes	No	Pre-cleaning of duodenoscopes reported to be delayed at times ("for over one-hour"). During periods of high volume, the number of certain cleaning adapters reportedly could be insufficient.	NR

Note: This list is not inclusive of all cases since 2012.

*The infections were not necessarily the cause of the deaths and could have been due to other underlying medical problems (eg, cancer, liver failure).

†The bacteria collected from the tested duodenoscope may be, but are not necessarily, the outbreak’s strain.

‡This outbreak occurred in 2008, but its details were not published until 2013.

§Some of the traits of these two cases are similar, although their relationship, if any, is unknown, unclear and could be coincidental (ie, case number 4 and 11).

¶These infections occurred in 2008 and 2009 and were reported to the FDA in 2015.

**ESBLs, or extended-spectrum beta-lactamases, are enzymes that bacteria, such as E. coli, may produce rendering the bacteria resistant to certain antibiotics.

††Some of the traits of these two cases are similar, although their relationship, if any, is unknown, unclear and could be coincidental (ie, case number 15 and 16).

AERs, automated endoscope reprocessors; CRE, carbapenem-resistant Enterobacteriaceae; EO, ethylene oxide; HLD, high-level disinfection; IFUs, instructions for use; MDRO, multidrug-resistant organism; NA, not applicable; NR, not reported.